Reader stop-layers

ABSTRACT

Tolerances for manufacturing reader structures for transducer heads continue to grow smaller and storage density in corresponding storage media increases. Reader stop layers may be utilized during manufacturing of reader structures to protect various layers of the reader structure from recession and/or scratches while processing other non-protected layers of the reader structure. For example, the stop layer may have a very low polish rate during mechanical or chemical-mechanical polishing. Surrounding areas may be significantly polished while a structure protected by a stop layer with a very low polish rate is substantially unaffected. The stop layer may then be removed via etching, for example, after the mechanical or chemical-mechanical polishing is completed.

SUMMARY

Implementations described and claimed herein provide a layered magneticstructure comprising one or more stop-layers that resist mechanicalpolishing of the layered magnetic structure without substantialdegradation and yield to chemical etching of the layered magneticstructure.

Other implementations provide a method of manufacturing a layeredmagnetic structure, comprising: depositing a stop-layer over a protectedcomponent of the layered magnetic structure; and mechanically polishingmaterial adjacent the protected component without causing significantrecession of the stop layer.

Still other implementations provide a read element comprising: one ormore stop-layers that resist mechanical polishing of the read elementwithout degradation and yield to chemical etching of the read element,wherein at least one of the one or more stop layers are deposited withina vacuum over one or more free layers and spacer layers of the readelement.

Other implementations are also described and recited herein.

BRIEF DESCRIPTIONS OF THE DRAWINGS

FIG. 1 illustrates an example air-bearing surface of a transducer headwith a read element manufactured using one or more stop-layers.

FIG. 2A illustrates an example air-bearing surface of a lower shield.

FIG. 2B illustrates the example lower shield of FIG. 2A with a shieldstop-layer deposited thereon.

FIG. 3A illustrates an example air-bearing surface of a lower shieldwith a shield stop-layer, a carbon layer, and a photo-resist layerdeposited thereon.

FIG. 3B illustrates the example lower shield, shield stop-layer, carbonlayer, and photo-resist layer of FIG. 3A with a depression formed in thelower shield.

FIG. 4A illustrates an example air-bearing surface of a lower shieldwith a shield stop-layer, a carbon layer, a photo-resist layer, and analumina layer deposited thereon.

FIG. 4B illustrates the example lower shield, shield stop-layer, carbonlayer, photo-resist layer, alumina layer, and alumina insert of FIG. 4Awith an insert stop layer deposited thereon.

FIG. 5A illustrates an example air-bearing surface of a lower shieldwith a shield stop-layer and a carbon layer deposited thereon, whereinre-deposition formed from removal of one or more layers are formed aboutan alumina insert protruding from a depression formed in the lowershield.

FIG. 5B illustrates the example lower shield, shield stop-layer, carbonlayer, alumina insert, and insert stop-layer of FIG. 5A with there-deposition removed.

FIG. 6A illustrates an example air-bearing surface of a lower shieldwith a shield stop-layer deposited thereon and a stop layer cappedalumina insert protruding from a depression formed in the lower shield,with a carbon layer removed.

FIG. 6B illustrates the air-bearing surface of the lower shield and thealumina insert of FIG. 6A, wherein some or all of the alumina insertthat had been protruding above the air-bearing surface of the lowershield is removed.

FIG. 7A illustrates an example air-bearing surface of a lower shieldwith a shield stop-layer removed and an alumina insert in the lowershield reduced to a common plane with the lower shield.

FIG. 7B illustrates the air-bearing surface of the lower shield and thealumina insert of FIG. 7A with a tri-layer read element and a readelement stop-layer deposited thereon.

FIG. 8A illustrates an example air-bearing surface of a lower shield andan alumina insert with a tri-layer reader, a reader stop-layer, and aphoto-resist layer deposited thereon.

FIG. 8B illustrates the lower shield, the alumina insert, the tri-layerreader, the reader stop-layer, and the photo-resist layer of FIG. 8A,with a photo mask placed over the photo-resist layer.

FIG. 9A illustrates an example air-bearing surface of a lower shield andan alumina insert with a tri-layer reader, a reader stop-layer, and aphoto-resist structure defined by a photo mask.

FIG. 9B illustrates the lower shield and the alumina insert of FIG. 9Awith areas of the tri-layer reader and the reader stop-layer notprotected by the photo-resist structure removed.

FIG. 10A illustrates an example air-bearing surface of a lower shieldand an alumina insert with a tri-layer reader structure, a readerstop-layer, and a photo-resist structure covered by an alumina layer.

FIG. 10B illustrates the lower shield, the alumina insert, the tri-layerreader structure, the reader stop-layer, the photo-resist layer, and thealumina layer of FIG. 10A with a metallic layer deposited thereon.

FIG. 11 illustrates an example air-bearing surface of a lower shield andan alumina insert with a tri-layer reader structure, a readerstop-layer, an alumina layer, and a metallic layer, with portions of themetallic layer, the alumina layer, and a photo-resist layer above thetri-layer reader structure removed and re-deposition remaining.

FIG. 12 illustrates example operations for preparing a lower shield withan integrated alumina insert for manufacturing a read element using oneor more stop-layers.

FIG. 13 illustrates example operations for depositing a read elementonto a lower shield with an integrated alumina insert using one or morestop-layers.

DETAILED DESCRIPTIONS

Information and communication systems increasingly handle huge amountsof data, placing heavy demands on magnetic media storage capacity andperformance. A transducer head on a magnetic storage media typicallyincludes a read element for retrieving magnetically encoded informationstored on a magnetic disc. Magnetic flux from a surface of the magneticdisc causes rotation of a magnetization vector of one or more sensinglayers of the read element, which in turn causes a change in electricalresistivity of the read element. The changes in electrical resistivityof the read element are correlated to the magnetically encodedinformation stored on the magnetic disc. Improvements in magneticstorage media technology allow areal recording densities on the magneticdiscs that are available today. However, as areal recording densitiesincrease, smaller, more sensitive read element heads are desired. As theread elements are made smaller and more sensitive, one or morestop-layers may be used during read element manufacturing to protectsome layers of the read element while simultaneously processing otherlayers of the read element.

FIG. 1 illustrates an example air-bearing surface of a transducer head100 with a read element 102 manufactured using one or more stop-layers(not shown). The transducer head 100 is a laminated structure with avariety of layers performing a variety of functions. A nonmagnetic,non-conductive substrate 104 (e.g., Al₂O₃, aluminum oxide, or alumina)serves as a mounting surface for the transducer head 100 components andconnects the transducer head 100 to an air-bearing slider (ABS) (notshown). A read element 102 is sandwiched between lower shield 106 and anupper shield 108. Shields 106, 108 isolate the read element 102 fromelectromagnetic interference, primarily y-direction interference, andserve as electrically conductive first and second electrical leadsconnected to processing electronics (not shown). In one implementation,shields 106, 108 are constructed of a soft magnetic material (e.g., aNi—Fe alloy).

Further, the lower shield 106 incorporates an alumina insert 120. Thealumina insert 120 is protected during manufacturing using one or morestop layers (e.g., ruthenium, chromium, and tantalum layers). The stoplayers have very low and consistent polish rate under abrasive polishing(e.g., polishing with an abrasive slurry) and chemical-mechanicalpolishing (e.g., polishing with an abrasive and corrosive chemicalslurry). In one implementation, the stop layers resist substantialrecession during abrasive polishing and/or chemical-mechanical polishing(e.g., has a recession rate of less than 2 Angstroms per minute).Further, the stop layers may readily dissolve in etching processes. Inother implementations, the upper shield 108 incorporates an aluminainsert in addition or in lieu of the alumina insert 120. The lowershield 106 and/or read element 102 may also be protected duringmanufacturing using one or more stop layers.

Resistance of the read element 102 changes as magnetic regions on amagnetic media come in close proximity to the read element 102. Whensense current is conducted through the read element 102 between the twoshields 106, 108, changes in read element 102 resistance yields changesin readback voltage that are tracked by the processing electronics.Thus, the readback voltage corresponds to polarity of the magneticregions on the media.

The transducer head 100 also includes nonmagnetic, non-conductiveinsulation layers 112 (e.g., alumina), which electrically isolate thelower shield 106 and the read element 102 from soft magnetic ornon-magnetic metallic side shields 110. As a result, substantially allthe current flowing between the shields 106, 108 must pass through theread element 102. The alumina insert 120 tunes the electrical resistancebetween the shields 106, 108 to a desired level. Further, the length ofthe read element 102 in the z-direction (i.e., stripe height) affectsthe overall resistance of the read element 102. As a result, aluminainsert 120 size and shape as well as the stripe height may be optimizedto provide a desired level of resistance and desired response amplitude.Further, the side shields 110 isolate the read element 102 fromelectromagnetic interference, primarily x-direction interference and/orz-direction interference.

The transducer head 100 also includes a barrier layer 114 between a coil116 and the shield 108. The coil 116 in combination with a write pole118 receives a write signal from the processing electronics and changesthe magnetic polarization of magnetic regions on an adjacent magneticmedia (not shown), thereby writing the data from the write signal to themagnetic media.

Portions of the soft magnetic side shield 110, the upper shield 108, andthe barrier layer 114 are shown as removed in the close-up view of FIG.1 for clarity purposes. The read element 102 is depicted as a trilayerread element. More specifically, the read element 102 includes at leastthree laminated metallic layers: a first ferromagnetic free layer 124, anonmagnetic spacer layer 126, and a second ferromagnetic free layer 128.The read element 102 is capped with a stop layer 130 to preventrecession of the trilayer stack during manufacturing processes. The freelayers 124, 128 each may be composed of magnetic materials such asnickel-iron-cobalt (Ni—Fe—Co) alloys. The stop layer 130 may be composedof particularly hard and non-reactive metals (e.g., ruthenium, chromium,and tantalum layers). In various implementations, the spacer layer 126may be relatively electrically conducting or non-conducting and servesto magnetically separate the free layers 124, 128 from one another.Further, the read element 102 is depicted with an expanding width in thex-direction with depth in the negative z-direction.

Magnetic flux from a surface of the magnetic media causes rotation of amagnetization vector of each of the free layers 124, 128 of the readelement 102, which in turn causes a change in electrical resistivity ofthe read element 102 between shields 106, 108. The changes in electricalresistivity of the read element 102 are correlated to magneticallypolarized regions on the magnetic media, which in turn correspond tostored data on the magnetic media.

The polarity of each of the free layers 124, 128 is affected by nearbymagnetic fields. A magnet 122 is mounted behind (in the negativez-direction) the read element 102. Other locations of the magnet 122 arecontemplated herein. The magnet 122 may be fabricated from permanentmagnet material such as a cobalt-platinum (Co—Pt) alloy. The magnet 122biases the magnetization of each of the two free layers 124, 128generally parallel to the magnetic media and converging in a“scissor-like” orientation with respect to one another. As the freelayers 124, 128 pass in close proximity to polarized magnetic regions onthe adjacent magnetic media, the polarization of the magnetic regionsaffects the polarity of each of the free layers 124, 128 and in turnaffects read element 102 resistance between the shields 106, 108. Morespecifically, a first magnetic region polarization may increase theangle of magnetization between the two free layers 124, 128 and a secondmagnetic region polarization may decrease the angle of magnetizationbetween the two free layers 124, 128. Sense current flows into the readelement sensor through the shields 106, 108 (which act as electrodes)and a change in resistance affects a readback voltage. As a result, themagnetic orientation of data on the magnetic media is detected bychanges in the readback voltage.

One implementation of the presently disclosed technology utilizes thefollowing materials and thicknesses. The free layers 124, 128 may bemade of various alloys containing nickel, iron, cobalt, and/or boron andhave thicknesses ranging from 20-50 A, for example. The spacer layer 244may be made of alumina, zinc oxide, calcium oxide, and/or magnesiumoxide and have a thickness ranging from 0-10 A, for example. The sideshields 110 may be made of NiFe alloys and have a thickness ranging from50-200 A, for example. Each of the top and bottom shields 106, 108 maybe made of NiFe alloys and have a thickness ranging from 1-2 microns,for example.

Other implementations of a read element 102 have a variety of size andshape orientations. The size and shape of read element 102 is an exampleonly. The presently disclosed technology may also be used with readelement types other than trilayer read elements as depicted herein(e.g., anistropic magnetoresistive (AMR) sensors, giant magnetoresistive(GMR) sensors including spin valve sensors and multilayer GMR sensors,and tunneling giant magnetoresistive (TGMR) sensors).

The transducer head 100 is configured to be attached to an air-bearingslider (not shown) at a distal end of an actuator arm flexure (notshown). The slider enables the transducer head 100 to fly in closeproximity above a corresponding surface of the adjacent magnetic media.The air-bearing surface of the transducer head 100 is configured to facethe magnetic media. The actuator arm flexure is attached to acantilevered actuator arm (not shown) and the actuator arm flexure isadjustable to follow one or more tracks of magnetic data on a magneticmedia (not shown). Electrical wires (not shown) extend along theactuator arm flexure and attach to contact pads (not shown) on theslider that ultimately connect to the transducer head 100. Read/writeand other electrical signals pass to and from processing electronics(not shown) to the transducer head 100 via the electrical wires andcontact pads.

FIG. 2A illustrates an example air-bearing surface of a lower shield206. The lower shield 206 is shown as viewed from a magnetic medialooking upwards at the air-bearing surface (x-y plane) of the lowershield 206. The lower shield 206 functions as a first electricalconnection for conducting a sense current through a read elementperpendicular to the major planes of the layers of a read element. Sidesand a bottom of the lower shield 206 are surrounded by a nonmagnetic,non-conductive substrate 204 (e.g., alumina). The substrate 204 servesas a mounting surface for the read element components (e.g., the lowershield 206) and connects the read element to an air-bearing slider (ABS)(not shown). In one implementation, the lower shield 206 is polishedbefore further processing as described below.

FIG. 2B illustrates the example lower shield 206 of FIG. 2A with ashield stop-layer 232 deposited thereon. The shield stop-layer 232 isdeposited over the lower shield 206 and the surrounding substrate 204 toprevent recession of the lower shield 206 during manufacturingprocesses. The lower shield 206 may be referred to herein as a protectedlayer when referencing shield stop-layer 232. The stop layer 232 may becomposed of particularly hard and non-reactive metals (e.g., ruthenium,chromium, and tantalum layers) that resist chemical-mechanical polishing(CMP) processes. In one implementation, the stop layer 232 is thinenough to be transparent (i.e., between 5 and 100 angstroms). Thecomponents of FIGS. 2A and 2B are not drawn to scale and may omitportions of a transducer head (not shown) and/or read element (notshown) for clarity of the illustrations.

FIG. 3A illustrates an example air-bearing surface of a lower shield 306with a shield stop-layer 332, a carbon layer 334, and a photo-resistlayer 336 deposited thereon. The carbon layer 334 and the photo-resistlayer 336 are applied on top of the stop-layer 332 and have asemi-circular void pattern. The semi-circular void pattern is intendedto aid application of an alumina insert discussed in detail below. Inother implementations, the alumina insert has a profile other thansemi-circular. Thus, the void pattern in the carbon layer 334 and thephoto-resist layer 336 will vary depending upon the intended shape ofthe alumina insert.

FIG. 3B illustrates the example lower shield 306, shield stop-layer 332,carbon layer 334, and photo-resist layer 336 of FIG. 3A with adepression 338 formed in the lower shield 306. The depression 338 may beformed using ion milling. The photo-resist layer 336 protects areas ofthe lower shield 306 covered by the photo-resist layer 336 from the ionmilling process. The depression 338 receives an alumina insert asdiscussed in detail below. The components of FIGS. 3A and 3B are notdrawn to scale and may omit portions of a transducer head (not shown)and/or read element (not shown) for clarity of the illustrations.

FIG. 4A illustrates an example air-bearing surface of a lower shield 406with a shield stop-layer 432, a carbon layer 434, a photo-resist layer436, and an alumina layer 442 deposited thereon. The alumina layer 442is deposited over the photo-resist layer 436 and within a depression 438in the lower shield 406. The alumina layer 442 at least fills thedepression 438 and may exceed the depth of the depression 438. Thealumina layer 442 deposited inside the depression 438 is referred toherein as the alumina insert 420.

FIG. 4B illustrates the example lower shield 406, shield stop-layer 432,carbon layer 434, photo-resist layer 436, alumina layer 442, and aluminainsert 420 of FIG. 4A with an insert stop layer 440 deposited thereon.The insert stop layer 440 is deposited over the alumina layer 442 andthe alumina insert 420 and is intended to protect the alumina insert 420from recession during polishing operations around the depression 338 asdescribed in detail below. The alumina insert 420 may be referred toherein as a protected layer when referencing insert stop layer 440. Theinsert stop layer 440 may be composed of particularly hard andnon-reactive metals (e.g., ruthenium, chromium, and tantalum layers)that resist chemical-mechanical polishing (CMP) processes. In oneimplementation, the insert stop layer 440 is thin enough to betransparent (i.e., between 5 and 100 angstroms). The components of FIGS.4A and 4B are not drawn to scale and may omit portions of a transducerhead (not shown) and/or read element (not shown) for clarity of theillustrations.

FIG. 5A illustrates an example air-bearing surface of a lower shield 506with a shield stop-layer 532 and a carbon layer 534 deposited thereon,wherein re-deposition 544 formed from removal of one or more layers(e.g., the photo-resist layer 436 and/or alumina layer 442) are formedabout an alumina insert 520 protruding from a depression 538 formed inthe lower shield. The photo-resist layer 436 and/or alumina layer 442 ofFIG. 4 are removed, leaving re-deposition 544 of material surroundingthe depression 538. In some implementations, the photo-resist layer 436(and above alumina layer 442) is removed using a solvent, which does notaffect any of the other layers. As a result, imperfections in themilling of depression 538, application of the alumina insert 520, andapplication of an insert stop layer 540 are revealed when thephoto-resist layer 436 and/or alumina layer 442 are removed.

FIG. 5B illustrates the example lower shield 506, shield stop-layer 532,carbon layer 534, alumina insert 520, and insert stop-layer 540 of FIG.5A with the re-deposition 544 removed. The re-deposition 544 may beremoved with abrasive polishing and/or chemical-mechanical polishing ofthe carbon layer 534. The insert stop-layer 540 prevents the abrasivepolishing and/or chemical-mechanical polishing from significantlyremoving material from the alumina insert 520. In one implementation,the re-deposition 544 are up to 50 nm tall (in the y-direction) and theinsert stop-layer 540 is approximately 2 nm thick (in the y-direction).The 2 nm thick is sufficient to resist abrasive polishing and/orchemical-mechanical polishing of the 9 nm tall re-deposition 544. Thecomponents of FIGS. 5A and 5B are not drawn to scale and may omitportions of a transducer head (not shown) and/or read element (notshown) for clarity of the illustrations.

FIG. 6A illustrates an example air-bearing surface of a lower shield 606with a shield stop-layer 632 deposited thereon and a stop layer 640capped alumina insert 620 protruding from a depression 638 formed in thelower shield 606, with a carbon layer removed. The carbon layer 534 ofFIGS. 5A and 5B is removed in FIG. 6A. The carbon layer 534 may beremoved with a plasma etching process, an acid etching process, or achemical-mechanical polishing process, for example. The shieldstop-layer 632 protects the lower shield 606 from recession duringremoval of the carbon layer. The insert stop layer 640 protects thealumina insert 620 from recession during removal of the carbon layer.After the carbon layer is removed, an offset between the insert stoplayer 640 and the shield stop-layer 632 in the y-direction is revealed.A gap 646 that is not covered by stop layer material exists at theinterface between the lower shield 606 and the alumina insert 620.

FIG. 6B illustrates the air-bearing surface of the lower shield 606 andthe alumina insert 620 of FIG. 6A, wherein some or all of the aluminainsert 620 that had been protruding above the air-bearing surface of thelower shield 606 is removed. While the x-z planar top surface of thealumina insert 620 is protected from abrasive polishing and/orchemical-mechanical polishing by insert stop layer 640, the protrudingportion of the alumina insert 620 may be removed by a side-millingprocess (i.e., milling in the x-z plane). The side milling utilizes agap between the insert stop layer 640 and a shield stop-layer 632 thatis not covered by a stop layer material (see e.g., gap 646 of FIG. 6A)to mill alumina underneath the shield stop-layer 632 and thus remove theportion of the alumina insert 620 protruding above the air-bearingsurface of the lower shield 606.

As a result, the insert stop layer 640 is removed with the portion ofthe alumina insert 620 protruding above the air-bearing surface of thelower shield 606. The alumina insert 620 may also be polished at thispoint. The shield stop-layer 632 may protect the polished lower shield606 from scratches caused by polishing the alumina insert 620. In oneimplementation, a 3 nm thick (in the y-direction) shield stop-layer 632is sufficient to prevent polishing of the alumina insert 620 fromscratching the lower shield 606. The components of FIGS. 6A and 6B arenot drawn to scale and may omit portions of a transducer head (notshown) and/or read element (not shown) for clarity of the illustrations.

FIG. 7A illustrates an example air-bearing surface of a lower shield 706with a shield stop-layer (see shield stop-layer of FIG. 632) removed andan alumina insert 720 in the lower shield 706 reduced to a common planewith the lower shield 706. The shield stop-layer may be removed using anetchant, leaving the alumina insert 720 coplanar in the x-z plane withthe lower shield 706. In other implementations, the shield stop-layermay remain and assist deposition of a read element (see below).

FIG. 7B illustrates the air-bearing surface of the lower shield 706 andthe alumina insert 720 of FIG. 7A with a tri-layer read element 702 anda read element stop-layer 730 deposited thereon. The tri-layer readelement 702 includes at least three laminated metallic layers: a firstferromagnetic free layer 724, a nonmagnetic spacer layer 726, and asecond ferromagnetic free layer 728. The read element 702 is capped witha stop layer 730 to prevent recession of the tri-layer read element 702during manufacturing processes. One or more layers of the read element702 may be referred to herein as a protected layer when referencing readelement stop-layer 730. Portions of the first ferromagnetic free layer724, the nonmagnetic spacer layer 726, the second ferromagnetic freelayer 728, and the stop layer 730 are shown as removed in the close-upview of FIG. 7B for clarity purposes. For example, the firstferromagnetic free layer 724, the nonmagnetic spacer layer 726, thesecond ferromagnetic free layer 728, and the stop layer 730 may cover90% of a corresponding wafer before additional processing is completedon the tri-layer read element 702.

The read element stop-layer 730 may be composed of particularly hard andnon-reactive metals (e.g., ruthenium, chromium, and tantalum layers)that resist chemical-mechanical polishing (CMP) processes. In oneimplementation, the insert stop layer 440 is thin enough to betransparent (i.e., approximately 5 to 100 angstroms).

In one implementation, each layer of the tri-layer read element 702 andthe read element stop-layer 730 are deposited together without breakinga vacuum during the deposition process. This ensures that the readelement stop-layer 730 adheres to the top layer of the tri-layer readelement 702 without an oxidation layer there between. The components ofFIGS. 7A and 7B are not drawn to scale and may omit portions of atransducer head (not shown) and/or read element (not shown) for clarityof the illustrations.

FIG. 8A illustrates an example air-bearing surface of a lower shield 806and an alumina insert 820 with a tri-layer reader 802, a readerstop-layer 830, and a photo-resist layer 836 deposited thereon. Thephoto-resist layer 836 covers at least the tri-layer reader 802 and thereader stop-layer 830. The photo-resist layer 836 may also coversurrounding substrate 804 material.

FIG. 8B illustrates the lower shield 806, the alumina insert 820, thetri-layer reader 802, the reader stop-layer 830, and the photo-resistlayer 836 of FIG. 8A, with a photo mask 848 placed over the photo-resistlayer 836. The photo mask 848 is applied on top of the photo-resistlayer 836 and has a shape resembling a triangle with a rectangularextension from one of the points of the triangle. The photo-resist layer836 shape is intended to pattern the final shape of the tri-layer reader802 as discussed in detail below. In other implementations, thetri-layer reader 802 has a profile other than shown in FIG. 1B, forexample. Thus, the photo-resist layer 836 shape will vary depending uponthe intended shape of the tri-layer reader 802.

The photo mask 848 selectively shields the photo-resist layer 836 fromexposure to light during photolithography. The light develops areas ofthe photo-resist layer 836 that are exposed. In one implementation, thephoto mask 848 includes glass and chrome portions. The glass portionsallow light to penetrate to the photo-resist layer 836. The chromeportions reflect away light and shields the photo-resist layer 836 fromthe light. In a glass and chrome photo mask 848, the shape resembling atriangle with a rectangular extension from one of the points of thetriangle corresponds to the chrome or photo-transparent portion of thephoto mask 848, depending on whether the photo-resist layer 836 is apositive photo-resist or a negative photo-resist. More specifically, apositive photo-resist becomes soluble when exposed to light and anegative photo-resist becomes insoluble when exposed. A developerremoves the insoluble material. The components of FIGS. 8A and 8B arenot drawn to scale and may omit portions of a transducer head (notshown) and/or read element (not shown) for clarity of the illustrations.

FIG. 9A illustrates an example air-bearing surface of a lower shield 906and an alumina insert 920 with a tri-layer reader 902, a readerstop-layer 930, and a photo-resist structure 936 defined by a photo mask(see photo mask 848 of FIG. 8B). Areas of the photo-resist structure 936not protected from exposure to light by a photo mask are developed byphotolithography. In one implementation, photolithography does notdevelop any of the reader stop-layer 930. The reader stop-layer 930 mayprotect top layers of the tri-layer reader 902 from thephotolithography. A photo-resist structure 936 with a shape resembling atriangle with a rectangular extension from one of the points of thetriangle remains after photolithography.

FIG. 9B illustrates the lower shield 906 and the alumina insert 920 ofFIG. 9A with areas of the tri-layer reader 902 and the reader stop-layer930 not protected by the photo-resist structure 936 removed. In oneimplementation, an ion-milling process removes areas of the readerstop-layer 930 and tri-layer reader 902 not covered by the photo-resiststructure 936. As a result, the tri-layer reader 902 and the readerstop-layer 930 have a shape resembling a triangle with a rectangularextension from one of the points of the triangle remains afterion-milling. The shape corresponds to the photo mask 848 shape of FIG.8B. The components of FIGS. 9A and 9B are not drawn to scale and mayomit portions of a transducer head (not shown) and/or read element (notshown) for clarity of the illustrations. In some implementations, anadditional reader stop-layer may be applied to the sides of thetri-layer reader 902 to further protect the tri-layer reader 902 fromrecession.

FIG. 10A illustrates an example air-bearing surface of a lower shield1006 and an alumina insert 1020 with a tri-layer reader structure 1002,a reader stop-layer 1030, and a photo-resist structure 1036 covered byan alumina layer 1050. The alumina layer 1050 may also overlap ontosurrounding substrate 1004. The alumina layer 1050 forms the insulationlayers 112 depicted in FIG. 1. The alumina layer 1050 electricallyisolates the lower shield 1006 and the tri-layer reader structure 1002from soft magnetic side shields (see non-magnetic metallic layer 1052 ofFIG. 10B). In one implementation, the alumina layer 1050 is thin enoughto be transparent (e.g., between 10 and 90 angstroms).

FIG. 10B illustrates the lower shield 1006, the alumina insert 1020, thetri-layer reader structure 1002, the reader stop-layer 1030, thephoto-resist layer 1036, and the alumina layer 1036 of FIG. 10A with ametallic layer 1052 deposited thereon. The non-magnetic or soft magneticmetallic layer 1052 fills in areas adjacent the tri-layer readerstructure 1002 that were previously milled away. The metallic layer 1052forms the side shields 110 depicted in FIG. 1. The metallic layer 1052isolates the tri-layer reader structure 1002 from electromagneticinterference.

FIG. 11 illustrates an example air-bearing surface of a lower shield1106 and an alumina insert 1120 with a tri-layer reader structure 1102,a reader stop-layer 1130, an alumina layer 1150, and a metallic layer1152, with portions of the metallic layer 1152, the alumina layer 1150,and a photo-resist layer (not shown) above the tri-layer readerstructure removed and re-deposition 1144 remaining. A side millingoperation (milling in the x-y plane) removes an exposed portion of thealumina layer 1150 adjacent the photo-resist layer (see exposed portionof the photo-resist layer 1036 of FIG. 10B). The photo-resist layer thenis then removed and the alumina layer 1150 and non-magnetic or softmagnetic metallic layer 1152 above (in the y-direction) the readerstop-layer 1130 are lifted away. Re-deposition 1144 of material mayremain. In some implementations, the photo-resist layer is removed usinga solvent, which does not affect any of the other layers. As a result,imperfections in the milling of alumina layer 1150, for example arerevealed when the photo-resist layer is removed.

The re-deposition 1144 may be removed with abrasive polishing and/orchemical-mechanical polishing of the exposed portions of the metalliclayer 1152, alumina layer 1150, and reader stop-layer 1130. The readerstop-layer 1130 prevents the abrasive polishing and/orchemical-mechanical polishing from significantly removing material fromthe tri-layer reader structure 1102. In one implementation, a 40-secondchemical-mechanical polishing operation is sufficient to remove there-deposition and not significantly recess the tri-layer readerstructure 1102. For example, an approximately 8 nm thick readerstop-layer 1130 can resist the 40-second chemical-mechanical polishingoperation. Optionally, the reader stop-layer 1130 may be chemicallyetched away after the abrasive polishing and/or chemical-mechanicalpolishing. The components of FIGS. 11A and 11B are not drawn to scaleand may omit portions of a transducer head (not shown) and/or readelement (not shown) for clarity of the illustrations.

FIG. 12 illustrates example operations 1200 for preparing a lower shieldwith an integrated alumina insert for manufacturing a read element usingone or more stop-layers. A polishing operation 1205 polishes a lowershield for the read element. An applying operation 1210 applies astop-layer over the lower shield. The stop-layer protects the lowershield from scratches during further manufacturing processes asdiscussed below. As such, the lower shield may be referred to as aprotected layer. The stop-layer may comprise Ruthenium or other hardnon-magnetic materials.

A second applying operation 1215 applies a carbon layer and aphoto-resist layer over the lower shield. Each of the carbon layer and aphoto-resist layer have a patterned void that patterns an alumina insertin the lower shield as discussed in detail below. A milling operation1220 mills a depression in the lower shield through the void in thecarbon layer and the photo-resist layer. The depression is intended toreceive the alumina insert as discussed below. A depositing operation1225 deposits an alumina layer over the photo-resist layer and withinthe depression in the lower shield. The alumina layer at least fills thedepression in the lower shield and may exceed the depth of thedepression in the lower shield, thus forming an alumina insert.

A second depositing operation 1230 deposits a stop-layer over thealumina layer. The stop-layer protects the alumina insert from recessionduring further manufacturing processes as discussed below. As such, thealumina insert may be referred to as a protected layer. The stop-layermay comprise Ruthenium or other hard non-magnetic materials. A removingoperation 1235 removes the photo-resist layer and the portion of thealumina layer and stop-layer deposited on the photo-resist layer.Removing operation 1235 leaves re-deposition spikes of material aroundthe void in the carbon layer and alumina insert.

A second polishing operation 1240 polishes the re-deposition spikesaround the void in the carbon layer and the alumina insert. Thestop-layer over the alumina insert prevents the second polishingoperation 1240 from causing recession of the alumina insert. A removingoperation 1245 removes the carbon layer leaving the stop-layer cappedalumina insert slightly protruding above the stop layer capped lowershield.

A side milling operation 1250 side mills the alumina insert within thedepression in the lower shield. The side milling operation 1250 operatesthrough a gap in the stop-layer over the alumina insert and the stoplayer over the lower shield. The side mill removes the portion of thealumina insert protruding beyond the lower shield. The top-layer overthe alumina insert is also removed by removing the alumina insertprotruding beyond the lower shield. The alumina insert may also bepolished at this point. An etching operation 1255 etches away anyremaining stop-layer material on the alumina insert and/or the lowershield. In some implementations, the etching operation 1255 is notperformed and the stop-layer material on the alumina insert and/or thelower shield is left remaining.

FIG. 13 illustrates example operations 1300 for depositing a readelement onto a lower shield with an integrated alumina insert using oneor more stop-layers. A deposition operation 1305 deposits a readerstructure including reader stack layers with a stop-layer on top of thereader stack layers. In one implementation, the read element is atri-layer reader. The stop-layer protects the read element fromrecession during further manufacturing processes as discussed below. Assuch, one or more layers of the read element may be referred to asprotected layers. The stop-layer may comprise Ruthenium or other hardnon-magnetic materials.

A coating operation 1310 coats the reader structure and surroundingsubstrate with a photo-resist layer. A placing operation 1315 places amask over the reader structure patterning a read element. In oneimplementation, the mask includes glass and chrome portions. The glassportions allow light to penetrate to the photo-resist layer. The chromeportions reflect away light and shields the photo-resist layer from thelight. A photo-etching operation 1320 photo-etches the photo-resist awayleaving a read element shaped photo-resist layer under the mask.

A milling operation 1325 mills away the reader stack layers that are notunder the reader element shaped photo-resist layer. This forms thegeneral shape of the read element. A second depositing operation 1330deposits a layer of alumina over the read element and surrounding thelower shield. This layer of alumina forms the insulation layers 112depicted in FIG. 1, for example. The alumina layer electrically isolatesthe lower shield and the read element from soft magnetic side shields(see non-magnetic metallic layer below).

A third depositing operation 1335 deposits a non-magnetic orsoft-magnetic metallic filler material adjacent to and on top of theread element. The metallic filler material forms the side shields 110depicted in FIG. 1. The metallic filler material isolates the tri-readelement from electromagnetic interference. A removing operation 1340removes the photo-resist layer over the read element with the aluminaand metallic filler material on top of the photo-resist layer removed aswell. Removing operation 1340 leaves re-deposition spikes of material ontop of the read element.

Polishing operation 1345 polishes the re-deposition spikes remaining ontop of the reader stack without degrading the top layer of the readerstack. The stop-layer over the reader stack prevents the polishingoperation 1345 from causing recession of the reader stack. In someimplementations, the stop-layer over the reader stack is etched awayafter polishing operation 1345.

The above specification, examples, and data provide a completedescription of the structure and use of exemplary embodiments of theinvention. Since many embodiments of the invention can be made withoutdeparting from the spirit and scope of the invention, the inventionresides in the claims hereinafter appended. Furthermore, structuralfeatures of the different embodiments may be combined in yet anotherembodiment without departing from the recited claims.

What is claimed is:
 1. A read sensor comprising: a first stop layer thatprotects a directly adjacent shield element from recession during atleast one of chemical polishing and mechanical polishing of the readsensor, wherein the first stop layer has a thickness less than about 20angstroms.
 2. The read sensor of claim 1, further comprising: a secondstop layer that protects a directly adjacent alumina layer fromrecession during mechanical polishing of another adjacent layer.
 3. Theread sensor of claim 1, wherein the first stop layer protects a directlyadjacent alumina insert from recession during mechanical polishing ofadjacent re-deposition material.
 4. The read sensor of claim 2, whereinthe first stop layer is positioned between the shield element and thesecond stop layer.
 5. The read sensor of claim 1, wherein the first stoplayer comprises Ruthenium.
 6. A method of manufacturing a read sensor,comprising: depositing a first stop-layer directly adjacent to a shieldelement, wherein the first stop-layer protects the shield element fromrecession during at least one of chemical polishing and mechanicalpolishing of the read sensor, wherein the first stop layer has athickness less than about 20 angstroms.
 7. The method of claim 6,further comprising: depositing a second stop-layer that protects adirectly adjacent insulating layer from recession during mechanicalpolishing of the read sensor.
 8. The method of claim 7, wherein theinsulating layer is an alumina insert.
 9. The method of claim 7, whereinthe first stop layer is positioned between the shield element and thesecond stop layer.
 10. The method of claim 6, wherein the firststop-layer comprises Ruthenium.
 11. The method of claim 6, furthercomprising: mechanically polishing material adjacent the shield elementwithout causing significant recession of the first stop layer.
 12. Aread element comprising: a stop-layer that protects an adjacent layerfrom recession during at least one of chemical polishing and mechanicalpolishing of the read element, wherein the stop layer has a thicknessless than about 20 angstroms.
 13. The read element of claim 12, whereinthe stop layer is adjacent to re-deposition material.
 14. The readelement of claim 12, wherein the adjacent layer protected from recessionis a layer of a reader stack.
 15. The read element of claim 12, whereinthe adjacent layer protected from recession is an alumina insert. 16.The read element of claim 12, wherein the stop-layer protects one ormore free layers and spacer layers from recession during mechanicalpolishing of adjacent re-deposition material.
 17. The read element ofclaim 12, wherein the stop-layer comprises Ruthenium.
 18. The readelement of claim 12, wherein the stop-layer comprises at least one oftantalum and chromium.